Bug 2383037 - LLVM sometimes fails to correctly spill crbit on power9 and newer
Summary: LLVM sometimes fails to correctly spill crbit on power9 and newer
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: llvm
Version: rawhide
Hardware: ppc64le
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Tom Stellard
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-07-23 14:04 UTC by Paul Murphy
Modified: 2025-08-03 01:15 UTC (History)
14 users (show)

Fixed In Version: llvm-20.1.8-3.fc43 llvm-20.1.8-3.fc42
Clone Of:
Environment:
Last Closed: 2025-07-30 13:49:17 UTC
Type: ---
Embargoed:
tstellar: mirror+


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker FC-1870 0 None None None 2025-07-28 21:01:55 UTC
Red Hat Issue Tracker RHEL-88598 0 None None None 2025-07-23 14:05:20 UTC

Description Paul Murphy 2025-07-23 14:04:01 UTC
If building for power9 or newer, and a CR bit is spilled, LLVM may miscompile the code. This bug has been around for quite some time. It was exposed when building the rust toolchain with -mcpu=pwr9 on c9s (see RHEL-88598).

The upstream bug is https://github.com/llvm/llvm-project/issues/143989, a patch is pending with pr https://github.com/llvm/llvm-project/pull/146424.

Reproducible: Always

Steps to Reproduce:
1. Build rust package with a power9 minimum CPU.
2. Observe strange test failures in JSON formatted output.

Comment 1 Fedora Update System 2025-07-29 16:22:20 UTC
FEDORA-2025-18488216e7 (llvm-20.1.8-3.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2025-18488216e7

Comment 2 Fedora Update System 2025-07-30 07:31:36 UTC
FEDORA-2025-dd4673b64d (llvm-20.1.8-3.fc42) has been submitted as an update to Fedora 42.
https://bodhi.fedoraproject.org/updates/FEDORA-2025-dd4673b64d

Comment 3 Fedora Update System 2025-07-30 13:49:17 UTC
FEDORA-2025-18488216e7 (llvm-20.1.8-3.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 4 Fedora Update System 2025-07-31 01:31:59 UTC
FEDORA-2025-dd4673b64d has been pushed to the Fedora 42 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2025-dd4673b64d`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2025-dd4673b64d

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 5 Fedora Update System 2025-08-03 01:15:18 UTC
FEDORA-2025-dd4673b64d (llvm-20.1.8-3.fc42) has been pushed to the Fedora 42 stable repository.
If problem still persists, please make note of it in this bug report.


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